DESCRIPTION

Hostname is the program that is used to either set or display the cur-
rent host, domain or node name of the system. These names are used by
many of the networking programs to identify the machine. The domain
name is also used by NIS/YP.
GETNAME
When called without any arguments, the program displays the current
names:
hostname will print the name of the system as returned by the gethost-name(2) function.
domainname,nisdomainname,ypdomainname will print the name of the sys-
tem as returned by the getdomainname(2) function. This is also known as
the YP/NIS domain name of the system.
dnsdomainname will print the domain part of the FQDN (Fully Qualified
Domain Name). The complete FQDN of the system is returned with hostname--fqdn.
When called with one argument or with the --file option, the commands
set the host name, the NIS/YP domain name or the node name.
Note, that only the super-user can change the names.
It is not possible to set the FQDN or the DNS domain name with the dns-domainname command (see THEFQDN below).
The host name is usually set once at system startup in
/etc/rc.d/rc.inet1 or /etc/init.d/boot (normally by reading the con-
tents of a file which contains the host name, e.g. /etc/hostname).
THEFQDN
You can't change the FQDN (as returned by hostname--fqdn) or the DNS
domain name (as returned by dnsdomainname) with this command. The FQDN
of the system is the name that the resolver(3) returns for the host
name.
Technically: The FQDN is the name gethostbyname(2) returns for the host
name returned by gethostname(2). The DNS domain name is the part after
the first dot.
Therefore it depends on the configuration (usually in /etc/host.conf)
how you can change it. Usually (if the hosts file is parsed before DNS
or NIS) you can change it in /etc/hosts.
If a machine has multiple network interfaces/addresses or is used in a
mobile environment, then it may either have multiple FQDNs/domain names
or none at all. Therefore avoid using hostname--fqdn, hostname--domain and dnsdomainname. hostname--ip-address is subject to the
same limitations so it should be avoided as well.

OPTIONS

-a,--alias
Display the alias name of the host (if used).
-d,--domain
Display the name of the DNS domain. Don't use the command
domainname to get the DNS domain name because it will show the
NIS domain name and not the DNS domain name. Use dnsdomainname
instead.
-F,--filefilename
Read the host name from the specified file. Comments (lines
starting with a '#') are ignored.
addresses may resolve to the same name, therefore the output may
contain duplicate entries. Do not make any assumptions about the
order of the output.
-h,--help
Print a usage message and exit.
-i,--ip-address
Display the IP address(es) of the host. Note that this works
only if the host name can be resolved. Avoid using this option;
use hostname--all-ip-addresses instead.
-I,--all-ip-addresses
Display all network addresses of the host. This option enumer-
ates all configured addresses on all network interfaces. The
loopback interface and IPv6 link-local addresses are omitted.
Contrary to option -i, this option does not depend on name reso-
lution. Do not make any assumptions about the order of the out-
put.
-s,--short
Display the short host name. This is the host name cut at the
first dot.
-V,--version
Print version information on standard output and exit success-
fully.
-v,--verbose
Be verbose and tell what's going on.
-y,--yp,--nis
Display the NIS domain name. If a parameter is given (or --filename ) then root can also set a new NIS domain.

FILES

/etc/hosts/etc/sysconfig/network

NOTE

Note that hostname doesn't change anything permanently. After reboot
original names from /etc/hosts are used again.